1,537 research outputs found

    A model-based approach to correcting spectral irradiance data using an upward-looking airborne sensor (CASI ILS)

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    A number of aircraft sensors have the facility to measure spectral downwelling irradiance using a sensor mounted on the roof of the aircraft, but these data are rarely used for atmospheric correction. Part of the problem is that the attitude of the airborne platform is always changing during flight, even in stable conditions, so that direct use of data from an incident light sensor (ILS) can introduce errors into atmospheric correction methods. The continual motion of the ILS is used here to advantage, as a means to fit a sky radiance distribution model developed by Brunger and Hooper (1993) to data from the Itres Instruments CASI ILS. The inclination of the ILS sensor, due to changing aircraft attitude, is considered as the slope plane in the model. The selected model coefficients correspond to parameterised atmospheric conditions and represent atmospheric transmission and the proportion of direct:diffuse flux. The method was used to correct CASI ILS data acquired over a site in southern England. Comparison with spectral irradiance measured simultaneously on the ground shows that the method reduced the variability of the ILS data and also compensated for the effect of different flight directions. The sky radiance distribution at sensor level is also calculated by the model, and shows the characteristics of the sky conditions at the time of each flight

    Retrieval of at-sensor irradiance using Incident Light Sensor (ILS)

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    A number of aircraft sensors have the facility to measure spectral downwelling irradiance using a sensor mounted on the roof of the aircraft, but these data are rarely used for atmospheric correction. Part of the problem is that the attitude of the airborne platform is always changing during flight, even in stable conditions, so that direct use of data from an incident light sensor (ILS) can introduce errors into atmospheric correction methods. The continual motion of the ILS is used here to advantage, as a means to fit a sky radiance distribution model developed by Brunger and Hooper (1993) to data from the Itres Instruments CASI ILS. The inclination of the ILS sensor, due to changing aircraft attitude, is considered as the slope plane in the model. The selected model coefficients correspond to parameterised atmospheric conditions, i.e. clearness index and diffuse ratio. The ILS data corrected by the model are wellmatched to variations of irradiance measured at ground level during three flights. The radiance distribution at sensor level is also calculated by the model, and shows the characteristics of the sky conditions at the time of each flight

    Neutrino Oscillations and Collider Test of the R-parity Violating Minimal Supergravity Model

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    We study the R-parity violating minimal supergravity models accounting for the observed neutrino masses and mixing, which can be tested in future collider experiments. The bi-large mixing can be explained by allowing five dominant tri-linear couplings λ1,2,3 \lambda'_{1,2,3} and λ1,2\lambda_{1,2}. The desired ratio of the atmospheric and solar neutrino mass-squared differences can be obtained in a very limited parameter space where the tree-level contribution is tuned to be suppressed. In this allowed region, we quantify the correlation between the three neutrino mixing angles and the tri-linear R-parity violating couplings. Qualitatively, the relations λ1<λ2λ3| \lambda'_1 | < | \lambda'_2| \sim | \lambda'_3|, and λ1λ2|\lambda_1| \sim |\lambda_2| are required by the large atmospheric neutrino mixing angle θ23\theta_{23} and the small angle θ13\theta_{13}, and the large solar neutrino mixing angle θ12\theta_{12}, respectively. Such a prediction on the couplings can be tested in the next linear colliders by observing the branching ratios of the lightest supersymmetric particle (LSP). For the stau or the neutralino LSP, the ratio λ12:λ22:λ12+λ22|\lambda_1|^2: |\lambda_2|^2: |\lambda_1|^2 + |\lambda_2|^2 can be measured by establishing Br(eν):Br(μν):Br(τν)Br(e\nu): Br(\mu\nu) : Br(\tau\nu) or Br(νe±τ):Br(νμ±τ):Br(ντ±τ)Br(\nu e^\pm \tau^\mp ): Br(\nu\mu^\pm\tau^\mp) : Br(\nu\tau^\pm\tau^\mp), respectively. The information on the couplings λi\lambda'_i can be drawn by measuring Br(litbˉ)λi2Br(l_i t \bar{b}) \propto |\lambda'_i|^2 if the neutralino LSP is heavier than the top quark.Comment: RevTex, 25 pages, 8 eps figure

    Anti-inflammatory effect of low intensity ultrasound (LIUS) on complete Freund's adjuvant-induced arthritis synovium

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    SummaryObjectivesArthritis with intra-articular inflammation was accompanied by joint pain, swelling, and stiffness leading to significant functional impairment. Thus, regulation of joint inflammation is a good therapeutic approach for patients with arthritis. In this study, the effect of low intensity ultrasound (LIUS) applied to an adjuvant-induced arthritic rat model on the synovium was investigated.DesignSynovial inflammation was induced by complete Freund's adjuvant (CFA)-injection into the rat knee joint. LIUS (200 mW/cm2) was applied on the ipsilateral knee everyday for 10 min beginning 1 day after inflammation induction. The expression of proinflammatory factors and immunohistochemical staining pattern of the synovium were assessed.ResultsCFA induced an increase of the knee circumference that was significantly diminished by LIUS. Synovial membrane hyperplasia in the ipsilateral joint was also affected by LIUS. The inflammatory mediators, COX-1/2, IL-1β, and iNOS, but not TNF-α, in the synovial membrane were induced after 3 days, and they closely correlated with the degree of edema. In the synovial membrane, the expression of inflammatory mediators was reduced by LIUS. The chemoattractant chemokine receptor CCR5 also was involved. On immunohistochemical analysis, CFA caused increased infiltration of CD11b-positive cells in the synovium. After 3 days, neutrophils, myeloperoxidase (MPO)-positive cells filled the inflammatory core; later, monocytes and macrophages, ionized calcium binding adaptor molecule 1 (Iba1)-positive cells in the periphery infiltrated the core by day 5. LIUS markedly reduced CFA-induced inflammatory cells infiltration.ConclusionLIUS showed a potent anti-inflammatory effect in this animal arthritis model with reduced infiltration of inflammatory cells into the synovium

    Neutrino Mass from R-parity Violation in Split Supersymmetry

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    We investigate how the observed neutrino data can be accommodated by R-parity violation in Split Supersymmetry. The atmospheric neutrino mass and mixing are explained by the bilinear parameters ξi\xi_i inducing the neutrino-neutralino mixing as in the usual low-energy supersymmetry. Among various one-loop corrections, only the quark-squark exchanging diagrams involving the order-one trilinear couplings λi23,i32\lambda'_{i23,i32} can generate the solar neutrino mass and mixing if the scalar mass mSm_S is not larger than 10910^9 GeV. This scheme requires an unpleasant hierarchical structure of the couplings, e.g., λi23,i321\lambda_{i23,i32}\sim 1, λi33104\lambda'_{i33} \lesssim 10^{-4} and ξi106\xi_i \lesssim 10^{-6}. On the other hand, the model has a distinct collider signature of the lightest neutralino which can decay only to the final states, liW()l_i W^{(*)} and νZ()\nu Z^{(*)}, arising from the bilinear mixing. Thus, the measurement of the ratio; Γ(eW()):Γ(μW()):Γ(τW())\Gamma(e W^{(*)}) : \Gamma(\mu W^{(*)}) : \Gamma(\tau W^{(*)}) would provide a clean probe of the small reactor and large atmospheric neutrino mixing angles as far as the neutralino mass is larger than 62 GeV.Comment: 10 pages, 3 figures, version submitted to JHE

    Radiation from accelerated particles in relativistic jets with shocks, shear-flow, and reconnection

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    We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Strong magnetic fields generated in the trailing jet shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock. We have also begun study of electron acceleration in the strong magnetic fields generated by kinetic shear (Kelvin-Helmholtz) instabilities. Our calculated spectra should lead to a better understanding of the complex time evolution and/or spectral structure from gamma-ray bursts, relativistic jets, and supernova remnants.Comment: 6 pages, 4 figures, 2012 Fermi Symposium proceedings - eConf C12102

    A Detailed Analysis of One-loop Neutrino Masses from the Generic Supersymmetric Standard Model

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    In the generic supersymmetric standard model which had no global symmetry enforced by hand, lepton number violation is a natural consequence. Supersymmetry, hence, can be considered the source of experimentally demanded beyond standard model properties for the neutrinos. With an efficient formulation of the model, we perform a comprehensive detailed analysis of all one-loop contributions to neutrino masses.Comment: 27 pages Revtex, no figur

    Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube

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    We have studied the afterpulse of a hemispherical photomultiplier tube for an upcoming reactor neutrino experiment. The timing, the amplitude, and the rate of the afterpulse for a 10 inch photomultiplier tube were measured with a 400 MHz FADC up to 16 \ms time window after the initial signal generated by an LED light pulse. The time and amplitude correlation of the afterpulse shows several distinctive groups. We describe the dependencies of the afterpulse on the applied high voltage and the amplitude of the main light pulse. The present data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure
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